IPM advice for soybean growers

by Dominic Reisig, NC State University

There are many management efforts you can take before your soybean seed goes into the ground.

Some of these actions are simply insurance and some of them, like your choice of row-spacing and planting date, are the best insect management decision choice you’ll make all year.

Unlike corn, which has many yield-robbing seedling pests (i.e., sugarcane beetle, billbugs, grubs, etc.) and the ever-present threat of thrips in cotton, we have very few seedling pests to contend with in soybeans.

Also unlike corn and cotton, seed treatments are not economical in North Carolina soybeans. In fact, seed treatments and foliar over-sprays have been tested in both Virginia and North Carolina for over 10 years.

Across nearly 20 trial/locations, there was not a single yield loss recorded due to seedling pests. These trials were designed with the intent of creating a problem with insects.

In one case, thrips numbers were as high as 91 per seedling, a situation that would have killed a cotton plant.  There were no yield differences in this trial.

The odds are that very very few fields, in our state will benefit by increasing yield from an insecticidal soybean seed treatment. And just as an aside, neonicotinoid seed treatments will not kill kudzu bugs. Read on to learn more about the soybean seedling pest complex.

In Virginia and North Carolina, both thrips and bean leaf beetle are a non-issue in terms of soybean yield when they infest seedlings. Do not scout or treat (or use seed treatments) for either of these pests.

Grasshoppers, katydids, and cutworms tend to be a problem in fields with lots of residue (think no-till) and fields that have not been properly rotated. They are also more of a problem on field edges.

These should be controlled with a pyrethroid if they begin to reduce stand levels to densities below those recommended by North Carolina Cooperative Extension.

Slugs, which are also more of a problem in no-till fields, are more difficult to control, as insecticides are ineffective. They are more of a problem when conditions are cool and wet which tend to be early on in the season.

Read the rest in Southeast Farm Press

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